Briefly considering the minor league careers of Yadier Molina, Carson Kelly

As part of his relentless spring training coverage for the St. Louis Post Dispatch and STLToday.com, beat writer Derrick Goold wrote yesterday about how the Cardinals have reached a point where they must begin considering the heir to Yadier Molina. While Molina is under contract through 2017 with a team option for 2018, it cannot be denied that the eight-time Gold Glover has entered the twilight stage of his MLB career.

Considered one of the most durable catchers of the decade, Molina has dealt with significant thumb injuries in each of the last two seasons, causing him to miss extended time and most importantly, leading to his absence in key postseason games. The Cardinals, understanding that Tony Cruz was not a realistic answer at backup, went out and signed free agent Brayan Pena to a two-year deal. At 34 years of age, Pena is not, by any means, a long-term solution, but he is definitely an upgrade over Cruz, particularly at the plate, and theoretically, he should get plenty of playing time at the beginning of the season (medical staff, please don't rush Yadi back).

Thus, who is currently being primed to be "Yadi's heir"? First and foremost, such a consideration is an unfair expectation of any catching prospect. Molina, a seven-time All Star, is a once-in-a-decade type catcher and it is highly unlikely for his eventual replacement to match his career production, both offensively and defensively. That being said, Carson Kelly, the Cardinals' second-round draft pick in 2012, is likely the closest prospect to fit the "Yadi's heir" mold.

Molina's Minor League Statistics

When looking at the slash line statistics of batting average, on-base percentage, and slugging, Molina was slightly better than a league average hitter in the rookie Appalachian League for Johnson City, in the Midwest League for Peoria, and in the Southern League (Double-A) for Tennessee.

Not until his age-21 season did Molina "break out" as a hitter in the minors, and even then, he was still well below the Pacific Coast League-average in slugging (.372 versus .452). Yet, this performance, combined with a team need at the big league level, led to his eventual promotion to back up Mike Matheny. In 2005, Molina became the full-time starter, and cliché alert, the "rest is history."

Kelly's Minor League Statistics

Plain and simple, Kelly's slash lines are a lot less glamorous than minor league Molina's. However, the 18 year old was probably pushed too quickly to full-season ball in 2013, as shown by his bounce back with Short-Season State College, so it is tough to blame him solely for a sluggish hitting performance. Then in 2014, the third baseman underwent a drastic positional change to catcher, again providing a good reason as to why his bat wasn't as potent as the organization once expected.

But last year was supposed to be the year for Kelly's bat to break out as his transition to catcher, just one year prior, had gone seamlessly (and sure enough, he was eventually awarded a minor league Gold Glove for his defense behind the plate). There was one major obstacle to this happening, though. Kelly was stuck in the pitcher-friendly confines known as the Florida State League.

The league-average slash line last season was .248/.313/.337. While Kelly lagged significantly in the batting average and on-base percentage departments, his overall slugging percentage should be considered a silver lining. Even further, post All-Star break, in 198 at bats, Kelly slashed .257/.296/.403—reaching a slugging percentage Molina barely reached in rookie league and one he couldn’t reach in the hitter-friendly Pacific Coast League the year of his MLB promotion.

Now, this consideration was not at all meant to be read as "all is well" for Carson Kelly in his development as a professional hitter because he definitely has plenty of work to do. However, given that he does not turn 21 until July and that he has yet to experience the privilege of hitting in the Texas League (with Double-A Springfield), I am willing to give him the benefit of the doubt. While it will almost certainly never reach Yadi's level, the defense is obviously there for Kelly. It is now time for the bat to follow—the same bat the Cardinals' scouting department raved about way back on draft day in 2012.